import os, sys

def main(arg1):
    s1 = os.path.join(arg1, "audio.m4s")
    s2 = os.path.join(arg1, "video.m4s")
    s3 = "%s.mp4" %os.path.basename(arg1)
    os.system("ffmpeg -i %s -i %s -codec copy %s" %(s1, s2, s3))

if __name__ == "__main__":
    if len(sys.argv) >=2:
        for i in sys.argv[1:]:
            main(i)
    else:
        print('\tpython3 *this [*biliVideoDir]...')
